Circadian variation in tolerance to the hypothermic action of CNS drugs

Alcohol Consumption Attenuates Febrile Responses to Lipopolysaccharide and Interleukin‐1β in Male Rats

“…For example, in mice, tolerance to repeated acute administration of EtOH developed when injections occurred in the light, but not in the dark, phase (Williams et al, 1993). Our data extend the results of Williams et al (1993) to chronic EtOH consumption insofar as we show that the dark-phase hypothermia and immobility induced by EtOH did not develop tolerance after 14 days of continuous exposure. Whether the lack of a hypothermic effect during the light phase after this regimen of EtOH consumption reflects tolerance remains to be determined.…”

Diurnal variation in nicotine sensitivity in mice: Role of genetic background and melatonin

“…Relative to the light/dark cycle, maximal sensitivity occurred during the latter half of the light phase and minimal sensitivity occurred during the latter half of the dark cycle. The heightened sensitivity to nicotine during the light phase of the light/dark cycle is consistent with the findings of Williams et al (Williams et al 1993) who found nicotine-induced hypothermia in rats to be greater during the light phase of the light/dark cycle. Of particular relevance is the finding that even during the period of the day where most experimental procedures are conducted (8AM to 6 PM), there is significant variability in sensitivity to nicotine.…”

“…Therefore, the daily pattern of smoking in humans may be due to daily variations in sensitivity to the effects of nicotine. Some support for this possibility comes from a limited number of studies that have shown that rats display a greater sensitivity to the locomotor and hypothermic effects of nicotine during the light versus dark phase of a normal 12 hour light/12 hour dark cycle (Williams et al 1993; Morley and Garner 1990). In addition, function and expression of α7 neuronal nicotinic receptors has been shown to vary in a time of day dependent manner.…”

Circadian Phase Determines Effects of Repeated Ethanol Vapor Exposure and Withdrawal on Body Temperature and Activity Rhythms of Male Mice

“…Acute EtOH injections (3 g/kg, intraperitoneally [i.p.]) elicit a 5°C drop in body temperature 1 hour before dark onset, but only 1.9°C 12 hours later (Williams et al., ). Compared with acute alcohol exposures, much less is known about how time‐of‐day modulates effects of long intoxication and withdrawal cycles typical of alcohol‐dependent subjects.…”